
    class Fish{
        int weight;
    }
    class Lake{
        Fish fish;
        void setFish(Fish s){
            fish = s;
        }
        void eat(int n){
            fish.weight = fish.weight + n;
        }
    }
    class FishandLake{
        public static void main(String[] args) {
            Fish niqiu = new Fish();
            System.out.println(niqiu.weight);
            Lake yangchenghu = new Lake();
            Lake taihu  = new Lake();
            yangchenghu.setFish(niqiu);
            taihu.setFish(niqiu);
            taihu.eat(15);
            System.out.println(niqiu.weight);
            System.out.println(yangchenghu.fish.weight);
            System.out.println(taihu.fish.weight);
            yangchenghu.eat(50);
            System.out.println(niqiu.weight);
            System.out.println(yangchenghu.fish.weight);
            System.out.println(taihu.fish.weight);
        }
    }

